OBJECTIVES: To study the mechanism of oxygenative activation of chemical carcinogens by liver microsomal P-450 oxygenase. APPROACH: In vitro metabolism of various chemical carcinogens and model compounds by rat liver microsomal P-450 oxygenase under various conditions. The products are extracted from the incubation mixture and analyzed qualitatively, quantitatively by: GLC, LC, TLC, MS, spectroscopy and reverse isotope dilution methods.